In general, a pneumatic tool is capable to perform various kinds of operations as while its pneumatic motor is driven by the compressed air. The pneumatic motor is able to rotate in a positive direction or a reverse direction by controlling airflow direction of the compressed air. Reference may be made to R.O.C. utility model publication No. 569885 entitled “Improved structure for airflow controlling mechanisms” provided an improvement of airflow controlling mechanism. It comprises a pneumatic cylinder having a cylinder body, an air chamber being formed in the cylinder body, a forward and a backward vents respectively passing through one end of the cylinder body for communicating the air chamber with outer side; an air valve having an annular body section, one end face of the air valve abutting against one end face of the cylinder body, two extension vents respectively extending through the body section, the openings of two ends of each extension vent being respectively positioned one end face of the body section and an inner circumference of the body section, the openings of the two extension vents positioned on the end face of the body section respectively communicating with the forward and backward vents; and an adjustment member having a base section coaxially accommodated in the body section, whereby the adjustment member can be turned between a clockwise position and a counterclockwise position, the circumference of the base section abutting against the inner circumference of the body section, an air passage radially extending through the base section, an opening of one end of the air passage being an outlet formed on the circumference of the base section for communicating with the air passage and a corresponding extension vent.
In the cited reference mentioned above, the compressed air passes through the air passage of the regulator, and enters the air vent of the positive direction through the extended air vents. As the pressure of compressed air is higher than the atmosphere pressure, the compressed air forms a pressure evening process in normal conditions with the lower ambient pressure and generates airflow to form an airflow kinetic force. The pneumatic tool employs this principle and the airflow kinetic force to drive a motor set. However, the question of the above conventional tools is that the regulator for controlling the positive and reverse rotations is located at the rear end of the pneumatic tool body. During operation users cannot control and alter the positive and reverse rotation easily by one hand. This causes a lot of inconveniences for the users in operation as they frequently need to hold the pneumatic tool and a work piece with two hands. The operation efficiency of the pneumatic tool also decreases.
The Applicant had filed an application with an air intake flow path control structure for pneumatic tools that allows users to operate single-handed, in this way they can hold a pneumatic tool at the mean time to start, stop or regulate the tool in positive or reverse rotations by one hand. The regulator for controlling the positive and reverse rotations of the pneumatic tools is located below the pneumatic tool body. Through a fastening element, the regulator is fastened to the cylinder. But the fastening element might has doubts with possibility of being loosened caused by vibration occurred and could result in leaking of the compressed air during operation of the pneumatic tools.
Hence, how to effectively transport the compressed air for users to facilitate control of positive and reverse rotation of the pneumatic tool and prevent the cylinder and the regulator from separating at the mean time is the goal for the applicants in this field to reach and issues remained to be overcome in the industry.
This invention aims to provide a novel design for pneumatic tools to allow users to operate single-handed, in this way they can hold a pneumatic tool at the mean time to start, stop or regulate the tool in positive or reverse rotations by one hand. Separation of the cylinder and the regulator also can be prevented. Operation convenience can be greatly improved as well.